This invention relates to fuel intake systems for internal combustion engines which use a primary fuel in which a secondary fuel is injected by a supplementary injection system. Still more particularly, this invention relates to such a supplementary injection system in which the secondary fuel comprises a mixture of alcohol and water which is electrically heated to a superheated gaseous state prior to injection into the intake system of the internal combustion engine.
A vast number of supplemental injection systems for internal combustion engines have been proposed in recent years to improve the economy and performance of conventional internal combustion engines. Several different systems have appeared in popular publications which involve the injection of water or water-alcohol liquid mixtures into the carburetor inlet of a conventional gasoline engine. These have all been relatively simple systems involving a remote tank for the water or water-alcohol mixture liquid, usually a pump, and a nozzle sprayer located in the air cleaner assembly such that the water or water-alcohol mixture may be sprayed directly into the carburetor throat during the operation of the gasoline engine.
A much more sophisticated system is disclosed in U.S. Pat. No. 4,244,328 to Lindstrom in which exhaust gases from an internal combustion engine are recirculated through a remote tank containing a lower alcohol which is reformed by the action of the heated exhaust gases to form a gaseous mixture of hydrogen and carbon monoxide which is then returned to the intake of the internal combustion engine with beneficial reduction in the amount of noxious components and aldehydes in the exhaust gas from the engine. A primary fuel preheating device is disclosed in U.S. Pat. No. 4,259,937 to Elliott. This device raises the temperature of the incoming gasoline to an effective level immediately upstream from the carburetor. No supplemental fuels or fuel mixtures are involved in this reference, however. Finally, U.S. Pat. No. 4,050,419 to Harpman et al discloses a hot fuel gas generator which superheats an incoming fuel mixture of gasoline and water to a very high temperature and then uses a primitive fuel injection system to convey the hot gaseous mixture combined with air to the intake manifold of the internal combustion engine. Only a single primary fuel plus water is utilized in this reference. A very similar system is disclosed in U.S. Pat. No. 4,114,566. Other references of interest include U.S. Pat. Nos. 4,031,864, 3,551,643, 3,498,279, 3,783,236, and 3,439,149.
Several of these systems, particularly the Harmpan and Elliott systems, are potentially very dangerous in that they electrically heat raw gasoline to a very high temperature. The potential for disasterous explosion is very real in these systems. None of the above references disclose a system in which a water and alcohol fuel mixture may be superheated to a gaseous state under relatively safe conditions for effectively controlled introduction into the intake system of a internal combustion engine powered by a different primary fuel, most commonly gasoline.